"Yes you can bring guns and amnunition but using them is the problem"
Thats true pretty much anywhere, I guess. I have often wondered, for example, if you can shoot clays off the back of a boat in The Chesapeake Bay. I have never checked into it because I'm not a clay shooter but just as a general question.
The whole "guns on board" thing is fraught with what seems to be a total conflicting bunch of laws everywhere...well, unless you are in Texas! I have been told in MD by different agencies that:
1. guns on board are NOT OK unless you are transporting them DIRECTLY to a gun shop or a shooting range , or a specific gun-related thing - same reg as transporting them in a "vehicle" because the boat is a vehicle. You can't legally stop anywhere enroute. IOW, you can't be coming back from the shooting range and stop to shop/eat lunch with the guns in the car. They have to be being transported directly home.
OR...
2. It's OK to have them on the boat because it's OK to have them at your home so if the boat is "your home" it's OK.
OR..
3. It's OK if the boat is "suitable as a home." As it was stated to me, it has to have "beds 'n heads" Obviously a 53 would meet this "requirement" but a center console, for example, would not.
If Mexican authorities inspect your vehicle when you cross into Mexico and find even a single expended cartridge case in your car/baggage, maybe from the last time you went target shooting, you go directly to prison. So it's important to be very aware of the actual regulations anywhere (state or country) you are carrying a gun...or happen to have an empty cartridge case.
OTOH, reading the regs may not be all that helpful. I have no idea what the REAL law is re a gun on board a boat in MD. I have read the actual regs and concluded that: Either 1 or 2, above is right, depending on how somebody - a judge, a law enforcement officer? - decides on any given day whether a boat is a home or a vehicle.
AND then...there is the issue of WHO is enforcing whatever laws. When we were boarded by the USCG for a random inspection near Oxford, MD two seasons ago, they didn't care at all if there were guns on board. But they did care about having a waste disposal plan!
BUT when we were boarded by local law enforcement in NY, the officer specifically asked if there were firearms on board. He didn't care about our waste disposal plan.